Rolling mill control apparatus



y 1962 F. D] NICOLANTONIO, JR., ETAI. 3,035,465

ROLLING MILL CONTROL APPARATUS Filed Sept. 25, 1957 2 Sheets-Sheet 1 Screwdown Motor Control Screwdown Device Digital Proqromer Fig.|.

WITNESSES INVENTORS Frank DiNicolontonio Jr. a R- wmord M. Brifluin.

ATTORNEY y 1962 F. DI NICOLANTONIO, JR, ETAI. $035,465

ROLLING MILL CONTROL APPARATUS 2 Sheets-Sheet 2 Filed Sept. 23, 1957 all 36959.1 32:00 3:20 32 N Ll W53 11? 3,935,465 Patented May 22, 1%62 3,035,465 ROLLING MILL CONTROL APPARATUS Frank Di Nicolantonio, .l'r., Lockport, and Willard M.

Brittain, Amherst, N.Y., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 23, 1957, Ser. No. 685,498 1 Claim. (Ci. 80-56) The present invention relates, in general, to control apparatus for a rolling mill, and more particularly to control apparatus for a rolling mill wherein said control apparatus is responsive to a control signal provided by a piece of material to be rolled either entering or leaving a particular stand of said rolling mill.

It is an object of the present invention to provide improved control apparatus for a roller device operative with a piece of material, wherein the pressure between the roller members is employed as an indication of the position of a workpiece and provides a control signal for controlling the operation of the roller device as may be desired.

it is another object of the present invention to provide improved rolling mill control apparatus, and more particularly to provide improved control apparatus for a rolling mill utilizing a magnetic sensing device to determine the position of a workpiece, such as a piece of material operative with said rolling mill, and to provide a signal for controlling the subsequent operation of one or more stands of the rolling mill relative to that same workpiece or other workpieces as may be desirable It is a further object of the present invention topro vide improved control apparatus for a rolling mill, which control apparatus is more rapidly responsive to the actual operation of the mill as may be desired for controlling the mill operation and to improve the efficiency of such operation.

It is an additional object of the present invention to provide improved control apparatus for a rolling mill, which apparatus is better responsive to the position of a workpiece as desired to improve the reversing operation of the mill relative to that workpiece as well as other desired operations of the mill relative to that workpiece, which other desired operations are dependent upon the position of said workpiece.

These and other objects and advantages of the present invention will become apparent in view of the following description taken in conjunction with the drawings, wherein:

FIGURE 1 is a schematic showing of the arrangement of the control apparatus in accordance with the present invention; and

FIG. 2 is an electrical schematic showing of the control apparatus of the present invention.

In FIG. 1 there is shown the housing of one stand of a rolling mill, including an upper roller member 12 and a lower roller member 14 which are adjustable in spacing as well known to persons skilled in this art by means of a screwdown device 16 for determining the thickness or gauge of a piece of material 18, such as a strip of steel, which passes between the roller members 12 and 14. The screwdown device 16 is provided with a motor 2% and a screwdown motor control 22 as well known to persons skilled in this art.

A magnetic strain gauge 24 including a fixed E-shaped core member 26 and a movable core member 28 is provided with the center leg of the E-shaped core member 26 having wound thereon a first control winding 30, a primary winding 32 and a second control winding 34. A regulated direct current voltage source 36 is connected to energize the primary winding 32. The two control windings 30 and 34 are connected to provide control signals to a control device 38 operative with a relay device i) for controlling the operation of a digital programming device 42 as will be later explained. The digital programming device 42 may be operative through a motor control 44 for controlling the operation of the mill motor 46 that is operative with the roller members 12 and 14. Other control functions, such as controlling the screwdown motor control 22 and the like may also be performed, as will be apparent to persons skilled in this particular art.

In FIG. 2 there is shown the voltage source 36 connected through a reactor member 50 and an adjustable resistor 52 to the primary winding 32 of the magnetic strain gauge device. The first control winding 30 of the magnetic strain gauge 24- is operative with a first transistor amplifier device T which amplifies the output signal from the first control winding 30 such that it can operate a flip-flop circuit 56 including a transistor T and a transistor T The second control winding 34 of the magnetic strain gauge 24 is operative with a similar transistor amplifier T The transistor amplifiers T and T are temperature compensated such that the output voltage of these amplifiers will not drift too excessively during ambient temperature changes. A first rate control circuit including a capacitor C and a resistor R is connected between the output of the transistor amplifier T and the base circuit of the transistor T in the flip-flop circuit 56. A second rate control circuit including a capacitor C and a resistor R is connected between the output of the transistor amplifier T and the base circuit of the transistor T in the flip-flop circuit 56. These rate control circuits keep the slow varying voltages from across the respective amplifiers T and T, from efiecting the operation ofthe flipfiop circuit 56. The diodes 2D and 5D keep any increasing negative signals from appearing on the flip-flop circuit 56, thus protecting the flip-flop circuit 56 from damaging increasing negative signals and also to prevent the flip-flop 56 from changing its operative state for an increasing negative signal.

The diode 1D and resistor R are operative with the first rate control circuit including the capacitor C and resistor R to prevent the capacitor C from charging up on an increasing negative signal such that when the increasing negative signal disappears, the capacitor C will have a very small voltage which cannot change the operative state of the flip-flop 56. The diode 6D and resistor R performs the same function relative to the rate circuit including the capacitor C and resistor R In the flip-flop circuit 56, the diode 4D assures that when the transistor T is not conducting it will not become conductive and the diode 3D assures that when the transistor T is not conducting it will not become conductive. The transistors T and T are operative as amplifier devices for operating the relay 58. When the relay 58 is energized, the contact member 59 closes a circuit operative with the digital programming device 62 for operating, for example, the screwdown motor 20 through the screwdown motor control 22. The digital programming device 62 may operate the mill motor 46 as shown in FIG. 1 for reversing the operation of the rolling mill if desired.

The magnetic strain gauge 24 as shown in FIG. 1 is mounted on the housing of the stand 10 of the rolling mill such that the Loom 28 is movable relative to the stationary E-core 26 and is so movable proportional to the stretch or strain in the housing 10 of the rolling mill including the roller members 12 and 14, which stretch is due to the roller pressure between the roller members 12 and 14. The primary coil 32 provided on the stationary E-core 26 is operative to establish a flux level in both the movable core 28 and the stationary core 26. The flux level for the latter cores is dependent upon the number of ampere turns of the primary winding 32 and also on the gap that exists between the movable core 28 and the stationary core 26. The secondary windings 30 and 34 are provided such that when a piece of material 18 enters the space between the roller members 12 and 14, or when the piece of material 18 leaves the space between the roller members 12 and 14, the gap between the stationary core 26 and movable core 28 will change. This change in gap will cause a voltage to appear on the stationary windings 30 and 34, which voltage is dependent on the equation a E- N where E is the voltage developed by the coil, N is the number of turns of the coil, and

M dt is the change in flux in the coil with respect to time.

The reactor 50 in series with the voltage source 36 and the primary winding 32 is provided to minimize any line voltage variation from effecting the voltage induced in the secondary windings 30 and 34. Since the voltage source '36 is a direct current voltage source, slow changing temperature effects relative to the gap between the movable core 28 and the stationary core 26 do not result in an appreciable induced voltage in the secondary windings 30 and 34.

When a workpiece either enters or leaves the space between the roller members 12 and 14, the resulting induced voltage in the secondary windings 30 and 34 may not be sufiicient to operate the flip-flop circuit 56 directly, and thusly, the voltage signals from the respective secondary windings 30 and 34 are amplified by the respective transistor amplifiers T and T which increase the signal level out of the respective secondary windings 30 and 34 a sufiicient amount to operate the flip-flop circuit 56.

The rate circuits including the capacitor C and resistor R in one such circuit and the capacitor C and resistor R in the other such circuit are operative to keep slow varying voltage changes in the respective secondary windings '30 and 34 from operating the flip-flop circuit 56.

When a workpiece enters the space between the roller members 12 and 14, a voltage is induced in the secondary winding 30 such that the base of the transistor T becomes more positive with respect to emitter to cause the transistor T to become conductive. However, the diode 2D is poled to short the resulting increasing negative control signal from the amplifier T At the same time, the secondary control winding 34 is provided with an induced voltage which makes the base of the transistor amplifier T more negative with respect to emitter which makes transistor amplifier T less conductive and turns On the transistor T in the flip-flop 56. This results in the base element of the transistor amplifier T 5 becoming less positive with respect to emitter such that the transistor amplifier T is turned Ofi to thereby result in the base element of the transistor amplifier T becoming more positive with respect to emitter to turn On the transistor amplifier T and thereby energize the winding of the relay device 58 from the voltage supply 61. When the relay device 58 is so operated, the contactor 59 closes its contacts to energize the digital programming device 62 to provide in accordance the punch markings on provided control punch cards or previously stored digital programming information the operation of the screwdovm motor 20 and the mill motor 46 and other devices that may be operative with the rolling mill 10, and as could be readily provided by persons skilled in this art after having the benefit of the teachings of the present invention.

As the workpiece leaves the space between the roller members 12 and 14, a control voltage is induced in the secondary winding 34 such that the base of the transistor T is made more positive with respect to emitter to thereby cause the transistor T to become more conducting. At the same time, a control voltage is induced in the secondary winding 30 which causes the base of the transistor T to become more negative with respect to emitter to make transistor T less conducting which causes the transistor T in the flip-flop circuit to turn On. With transistor T On, it will make transistor T turn Off, the base of the transistor amplifier T is made more positive with respect to emitter to turn On the transistor T to thereby turn Off the transistor T and thusly deenergize the relay device 53 relative to the voltage source 61.

In the operation of the control device, as shown in FIG. 2, lower frequency rate of change control signals are prevented from operating the flip-flop device 56 by the rate control circuits including the capacitor C and resistor R relative to the transistor T and the capacitor C and resistor R relative to the transistor T In addition, higher frequency rate of change voltage signals due to, for example, noise influences are prevented from operating the flip-flop device 56 by the capacitors C and C relative to the transistor device T and by the capacitors C and C relative to the transistor T It should be understood that the present control apparatus may be operative with a reversing rolling mill to reduce the thickness of a steel ingot down to the size of a bloom or slab as known to persons skilled in this art. In this regard, it may require twenty passes back and forth through the mill to effect the desired reduction and size of the ingot. Thusly, as the ingot first enters the space between the roller members 12 and 14, it may be desired to accelerate the mill in response to the control signal thereby received from the strain gauge 24. As the ingot subsequently leaves the mill, it may be then desirable to decelerate the mill by decreasing the speed of the mill motor 46. Further, as the ingot leaves the mill, it may be desirable to advance the digital programming device 42 to the information required for the second pass, and to reverse the operation of the mill, and to decrease the screwdown spacing through the screwdown motor control 22 and the screwdown motor 20. Then as the ingot enters the mill from the opposite side and in the opposite or reverse direction, then it is again desirable to accelerate the mill in response to the signal received from the strain gauge 24 and to subsequently decelerate the mill as the ingot leaves at the end of the second pass. Thusly, this operation may be repeated with the mill for each of the successive twenty or so passes through the rolling mill 10 as may be desired.

It should be further noted that alternating current energization of the strain gauge 24 may be suitable with a closely regulated alternating current voltage source substituted for the voltage source 36 as shown in FIGS. 1 and 2.

Although the present invention has been described with a certain degree of particularity, it should be understood that the present disclosure has been made only by Way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the scope and the spirit of the present invention.

We claim as our invention:

In control apparatus for a rolling mill operative in one direction and in the opposite direction and including a pair of roller members operative with a piece of material, the combination of a roller pressure sensing device for providing a control signal having a predetermined change in value when said piece of material changes the pressure between said roller members by a given amount within a selected time period, a mill control device operative with said mill for changing the direction of operation of said mill, and a rate of change device operative with said mill control device and responsive to said control signal when the value of said signal changes by said given amount within said selected period of time.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Pierre Oct. 17, 1939 Shayne et a1. Jan. 18, 1944 5 Shayne et a1 Feb. 22, 1944 6 Macaulay et a1 Nov. 24, 1953 Macaulay et a1. May 10, 1955 Anastasia et a1 Dec. 13, 1955 Russell Jan. 7, 1958 Fogiel Jan. 21, 1958 Peterson Apr. 8, 1958 

